The study was carried out by Veerabhadran Ramanathan a distinguished professor of climate and atmospheric sciences from the Scripps Institution of Oceanography at the University of California San Diego. Ramanathan and his colleague former Scripps graduate student Yangyang Xu examined the possible outcomes based around the targets set by the 2015 Paris Climate Agreement.

The Paris Agreement currently states that society keep average global temperatures below a 2 degrees increase from temperatures recorded during the height of the Industrial Revolution.

What the pair found was that even a small increase of just 1.5 degrees should still be categorised as “dangerous” resulting in substantial damage to human and natural systems.

Go beyond 3 degrees and the results would fall into the “catastrophic” category. Take the rise beyond 5 degrees and the results fall into “unknown”.

In case you’re wondering, “unknown” is very literal. Quite simply we have no idea how bad the damage would be, although both academics agree that it could result in potentially existential threats.

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While both “catastrophic” and “unknown” are both listed as “low-probability high-impact events” the pair still put their likelihood at around 5%.

“When we say 5 percent-probability high-impact event, people may dismiss it as small but it is equivalent to a one-in-20 chance the plane you are about to board will crash,” explains Ramanathan.

“We would never get on that plane with a one-in-20 chance of it coming down but we are willing to send our children and grandchildren on that plane.”

Despite having such a low probability, a 5 degree rise would cause what the pair call “tipping points” around the planet including the collapse of the West Antarctic Ice Sheet and the complete dieback of the Amazon rainforest.

Russell Cheyne / Reuters

It’s not all doom and gloom though. Both Ramanathan and Xu believe that preventing these outcomes is something that the global community is more than capable of doing.

Global CO2 emissions have dropped to near-zero levels while the boom in renewable energy has made a huge difference. Where progress needs to be made is in democratising renewable technologies across both the developed and developing worlds.